Mathew Marquis, Thu, 21 Jun 2012 23:30:08 +0000:
> a proposal for an adaptive image element to a W3C wiki here:
> http://www.w3.org/community/respimg/wiki/Picture_Element_Proposal
Regarding the proposal in the wiki, then it deviates from "the markup
pattern established by the HTML video element' in the following details:
* @src/@srcset is not allowed on the 'picture' container
<picture srcset="tall.jpg 1x, tall2.jpg 2x"></picture>
* @alt on the container element.
However, one argument against <picture> instead of an (overloaded)
@srcset on <img>, is <picture>’s (default) lack of support for the
<img> specific attributes such as @alt, @usemap and @ismap etc.
It also strikes me that, if first going for a <picture> element, then
there are many things one would want to consider, such as mark-up based
alternative text instead of attribute based alternative text.
One form of mark-up based alternative text could be to simply specify
alternative text to be provided via a child <img> element. One could go
even further, perhaps, and let the <img> child element also provide e.g.
the @usemap, @longdesc etc of the <picture>.
The following 3 examples are more <video> pattern adhering than the
example in the wiki:
Example 1: without @src/@srcset on container:
<picture>
<img src="fallback.jpg" alt='alternative text' />
<source media="(orientation:landscape)" srcset="long 1x,long2 2x">
<source media="(orientation:portrait)" srcset="tall 1x,tall2 2x">
</picture>
Example 2: with @src/@srcset on the container element:
<picture srcset="img 1x,img2 2x" >
<img src="fallback.jpg" alt='alternative text' />
</picture>
Example 3: Like example 2 but no @src on the <img> element:
<picture srcset="img 1x,img2 2x" >
<img alt='alternative text' />
</picture>
[1]
http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2012-May/036160.html
[2]
http://www.w3.org/mid/20120624050514401521.4e33ede6@xn--mlform-iua.no
--
Leif H Silli